What do you think of the end of "The Call of the Wild"? Is it happy or unhappy? What messages can be decoded from it?
While it is sad that Thornton was killed, Buck is able to run in the wild. Buck loved his master very much, Thornton saved him from cruel people and death, yet if he did not have Thornton he desired to be free.
Buck's trials show that freedom is to be treasured, and Buck had endured a lot to gain his freedom. Buck, by no means forgot his master, he resurfaced to visit Thornton's grave, and had avenged his murder.